Internal combustion engine lubricating system



A. E. KOLBE March 6, 1962 INTERNAL COMBUSTION ENGINE LUBRICATING SYSTEM9 Sheets-Sheet 1 Original Filed 001:. 1, 1959 m VENTOR /mm: 6. mi!

ATTORNEY A. E. KOLBE March 6, 1962 INTERNAL COMBUSTION ENGINELUBRICATING SYSTEM Original Filed Oct. 1, 1959 INVENTOR. .IdF/iym 6.56/5! ATTORNEY March 6, 1962 A. E. KOLBE 3,023,846

INTERNAL COMBUSTION ENGINE LUBRICATING SYSTEM Original Filed Oct. 1,1959 9 Sheets-Sheet 3 IN VEN TOR. Y fQk/Z/F/ 6 fi/fiz ,lmw

ATTORNEY March 6, 1962 A. E. KOLBE 3,846

INTERNAL COMBUSTION ENGINE LUBRICATING SYSTEM Original Filed Oct. 1,1959 9 Sheets-Sheet 4 INVENTOR.

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INTERNAL COMBUSTION ENGINE LUBRICATING SYSTEM Original Filed Oct. 1,1959 9 Sheets-Sheet 5 ii i3 #41 A?! w g z? W M 59 7 w i g a 55 INVENTOR.

ATTORNEY A. E. KOLBE March 6, 1962 INTERNAL COMBUSTION ENGINELUBRICATING SYSTEM 9 Sheets-Sheet 6 Original Filed Oct. 1, 1959INVENTOR. fit//kzf 6T $61k ATTORNEY March 6, 1962 A. E. KOLBE 3,023,846

INTERNAL COMBUSTION ENGINE LUBRICATING SYSTEM Original Filed Oct. 1,1959 9 Sheets-Sheet '7 IN VEN TOR.

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ATTORNEY March 1962 A. E. KOLBE 3,023,346

INTERNAL COMBUSTION ENGINE LUBRICATING SYSTEM Original Filed Oct. 1,1959 9 Sheets-Sheet 8 1 292 y w M/ Z? I}! w ,2

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ATTORNEY March 6, 1962 A. E. KOLBE 3,023,346

INTERNAL COMBUSTION ENGINE LUBRICATING SYSTEM 9 Sheets-Sheet 9 OriginalFiled Oct. 1, 1959 INVENTOR.

ATTORNEY 3,23,846 Patented Mar. 6, 1962 3,023,846 INTERNAL COMBUSTIONENGINE LUBRICAT- ING SYSTEM Adelbert E. Kolbe, Berkley, Micln, assignorto General Motors Corporation, Detroit, Mich, a corporation of DelawareOriginal application Oct. 1, 1959, Ser. No. 843,811. Di-

application Aug. 22, 1960, Ser. No.

vided and this 1 Claim. (Cl. 184-6) This application is a division ofapplication S.N. 843,811 filed October 1, 1959 in the name of AdelbertE. Kolbe.

This invention relates to lubricating systems for internal combustionengines, particularly to light weight, low cost engines for automotiveand other purposes.

The invention may be embodied in a 180 cylinder engine having acrankcase supporting at each end that contain the accessory devices inoperating the engine. One of these housings receives an end of thecrankshaft of the engine and from which the lubricating pump of theengine is driven. The lubricating pump is built into one of the housingsin such a way as to be accessible from the outside of the housing. Thepump circulates oil throughout passages in the housing which are adaptedto communicate with passages in the crankcase and elsewhere throughoutthe engine, and from which the principal working parts of the engine arelubricated. The passages in the housing circulate oil to variousaccessory devices supported by the housing and employed in operating theengine. The housing is sealed with respect to the crankcase and thevarious accessory devices are sealed with respect to the housing and thecrankcase so that the communicating passages formed in the differentengine parts may be sealed with respect to the exterior of the engineand to one another. Certain of these passages are formed partly indilferent parts of the engine to facilitate manufacture of the engineand so that the dilferent accessory devices and the various partsthereof may be easily manufactured and assembled and serviced.

In the drawings:

FIGURE 1 is a fragmentary longitudinal sectional view of a 180 opposedcylinder air cooled internal combustion engine having a lubricatingsystem embodying the principles of the invention.

FIGURE 2 is a cross-sectional view of the engine disclosed by FIGURE 1.

FIGURE 3 is an enlarged fragmentary view of one of the valve actuatingmechanisms of the engine.

FIGURE 4 is a cross-sectional view illustrating one of the end housingsembodied in the engine disclosed by FIGURES 1 and 2. FIGURE 4 shows theinside surface of the housing with various parts of the structure brokenaway to better illustrate the internal construction thereof. FIGURE 4 istaken substantially in the plane of line 44 on FIGURE 1, looking in thedirection of the arrows.

FIGURE 5 is a fragmentary cross-sectional view illustrating one side ofthe end of the engine to which the housing illustrated by FIGURE 4 issecured. FIGURE 5 is taken substantially in the plane of line 55 on FIG-URE 1, looking in the direction of the arrows.

FIGURE 6 is a fragmentary cross-sectional view of the inlet leading tothe lubricating oil pump of the engine as the inlet might appear in theplane of line 66 on FIG- URE 5, looking in the direction of the arrows.

FIGURE 7 is a cross-sectional view through the lubricating oil pumpembodied in the structure disclosed by opposed housings employed FIGURE4. FIGURE 7 is taken substantially in the plane 7 of line 77 on FIGURE4, looking in the direction of the arrows.

FIGURE 8 is a cross-sectional view in a different plane of thelubricating oil pump embodied in the structure disclosed by FIGURE 4. FlURE 8 is taken substantially in the plane of line 8- 8 on FIGURE 4,looking in the direction of the arrows.

FIGURE 9 is a cross-sectional view through the pressure relief valve forthe pump embodied in the structure disclosed by FIGURE 4. FIGURE 9 istaken substantially in the plane of line 99 on FIGURE 4, looking in thedirection of the arrows.

FIGURE 10 is a fragmentary view illustrating an oil metering jet forlubricating the drive means for the accessory and other devices embodiedin the crankcase of the engine and in the housing disclosed by FIGURE 4.FIGURE 10 is taken substantially in the plane of line 1010 on FIGURE 4,looking in the direction of the arrows.

FIGURE 11 is a fragmentary cross-sectional view through the accessoryhousing disclosed by FIGURE 4, and particularly illustrating the oilfilter and the association thereof with the lubricating system of theengine. FIGURE 11 is taken substantially in the plane of line 11 11 onFIGURE 4, looking in the direction of the arrows.

FIGURE 12 is a cross-sectional view through the oil filter mounterbracket embodied in the structure disclosed by FIGURE 11. FIGURE 12 istaken substantially in the plane of line 1212 on FIGURE 11, looking inthe direction of the arrows.

FIGURE 13 is another fragmentary cross-sectional view through theaccessory housing, the filter mounting bracket and a part of thecrankcase of the engine. FIGURE 13 is taken substantially in the planeof line 13-13 on FIG- URE 4, looking in the direction of the arrows.

FIGURE 14 is a fragmentary cross-sectional view illustrating a part ofthe means for lubricating the crankshaft and camshaft of the engine.FIGURE 14 is taken substantially in the plane of line 1=4-14 on FIGURE1, looking in the direction of the arrows.

FIGURE 15 is a fragmentary cross-sectional view of one of the cylindersof the engine and illustrating the lubrication of the piston pins of theengine.

FIGURE 16 is a cross-sectional view of the engine illustrating thelubrication line 17-17 on FIGURE 16, looking in the direction of thearrows.

ate walls 18 and 19 and between which bearings 21 for the crankshaft 22and bearings 23 for the camshaft 24 of the engine are formed. Thecrankshaft has journals 26 supported by the bearings 21 and the camshaft24 has journals 27 supported by the bearings 23.

The crankcase 11 has side walls 28 having rows of cylinder openingsformed therein and adapted to receive engine cylinders 29. The cylinders29 in each row have heads 31 which are secured to the cylinder and thecylinders to the side walls of the crankcase by bolts 32. The cylinders29 have reciprocating pistons 33 therein which are secured to thecrankarms 34 of the crankshaft 31 are formed to provide combustiontrolled by inlet valves 38 and exhaust chambers 37 convalves 39, theinlet valves 38 controlling inlet passages 41 and the exhaust valves 39controlling exhaust passages 42 which are formed in the heads 31 of theengine. The valves 38 and 39 are adapted to be closed by valve springs43 and opened by rocker arms 44 embodied in the valve actuatingmechanism for controlling the operation of the different cylinders ofthe engine. The rocker arms are supported on rocker arm supports 46which in the present instance are mounted in outer walls 47 of the heads31 and which threadably engage certain of the bolts 32 for securing thehead and the cylinders to the crankcase of the engine. The rocker arms44 are actuated by push rods 48 which are in turn actuated by valvelifters 49 that are mounted in bosses 51 which are formed in thecrankcase 11 of the engine in such position that the valve lifters willbe engaged by the cams 52 on the camshaft 24 of the engine. The heads 31have valve actuating mechanism covers 53 secured to the heads by bolts54. The push rods 48 also have valve actuating mechanism covers in theform of push rod conduits 56. The conduits 56 extend between openings inthe heads and openings in the crankcase so that the crankcase and thecompartments containing the rocker arms 44 may communicate around eachof the push rods 48.

The end wall 16 of the crankcase 11 is adapted to have a clutch anddrive gear housing 57 secured thereto by bolts 58. The housing 57 issealed against the end wall 16 by a gasket 55. The crankshaft 22 has anend 59 extending beyond the wall 16 of the crankcase 11 and through acavity 61 formed in the engine between the crankcase 11 and the housing57. A seal 62 in an opening formed in the housing 57 is adapted toengage a hub 63 on the crankshaft end 59 for sealing the cavity 61. Thehub '63 may have a clutch or other suitable device secured thereto andby which the engine may be employed in driving a motor vehicle or otherdevice. The inner part of the hub 63 within the cavity 61 is formed toprovide a drive gear 64 for driving another gear 66 in the cavity 61 andsecured to an end 67 of the camshaft 24 that projects within the cavity61. The crankshaft 22 drives the camshaft 24 through the gears 64 and 66in the cavity 61.

The opposite end of the crankcase 11 has a housing 68 secured to the endwall 17 by bolts 69. The housing 68 is sealed against the end wall 17 bya gasket 70. The housing 68 and the end wall 17 of the crankcase 11 arealso formed to provide a cavity 71 in which the other end 72 of thecrankshaft 22 projects. The outer part of the end 72 supports a hub 73having a drive pulley 74 secured thereon and which may be employed fordriving various accessory devices for the engine. One of these devicesmay be a blower mounted on an upper wall 76 of the crankcase 11 andemployed in circulating air over the fins formed on the cylinders 29 andthe heads 31 for cooling the engine. The hub is engaged by a seal 77which is secured in an opening in the housing 68 and in which the hub 73and the shaft end '72 are operatively disposed. The housing 68 has abracket'78 which is secured to an upper surface thereof by bolts 79 andin such position that a cavity 81 in the lower part of the bracket willcommunicate with the cavity 71 through a passage 82 in the upper part ofthe housing. A gasket 80 is employed in sealing the bracket 78 to thesurface of the housing 68 on which the bracket is secured by bolts 79.

An oil filler tube 83 is secured in a passage 84 leading to the cavity81 and in a position to supply oil to the cavity 71 when the cap 86 forthe filler tube 83 is removed. The lower part of the cavity 71 extendsdownwardly in the housing 68 to a position directly opposite the opening87 in the wall 17 of the crankcase 11 so that the oil supplied to thecavity 71 when the cap 86 is removed will flow downwardly into thecrankcase through the passage 82. The lower part of the crankcase 11 isclosed by an oil pan 88 which is secured to the end walls 16 and 17 andside walls 28 by screws 89. The oil pan 88 provides a sump 91 adapted tocontain the lubricating oil so supplied to the crankcase 11. The oilsump 91 contains a screened inlet 92 which is connected by a conduit 93to a cavity 94 in the end wall 17 of the crankcase 11. The cavity 94communicates with an inlet passage 96 in the housing 68 which terminatesin an inlet port 97 for a lubricating oil pump 98 that is also disposedin the housing 68. The pump 98 in the present instance includes meshinggears 99 and 101 adapted to rotate in a cavity 102 formed in the lowerpart of the housing 68, the cavity being closed beyond the gears by aplate 103 secured to the housing by bolts 104. A gasket 106 securedbetween the plate and the housing is adapted to seal the pump 98 againstleakage. The gear 101 is rotatably mounted on a shaft 107 secured in anopening through a projection 108 extending outwardly from the housing68. The shaft 107 is pressed into the opening in the projection 108 toprevent leakage of oil around the shaft. When the plate 103 is removed,it will be possible to remove the gear 101 which is rotatably mounted onthe lower end of the shaft 107. The gear 99 is pressed onto the lowerend of a shaft 109 that is rotatably mounted in a bearing 111 formed inthe housing 68. When the plate 103 is removed it is possible to removethe gear 99 and the shaft 109. The shaft 109 is adapted to be driven bya shaft 112 through a coupling 113 formed by the tongue and slotted endsof the two shafts. The lower end of the shaft 107 also projects into andis rotatably supported in the bearing 111. The upper end of the shaft112 is secured in an opening formed in a gear 114 that has a hub 116 inwhich the lower end of a distributor shaft 118 is also secured. The gear114 is driven by a driving gear 119 keyed at 121 to the end 72 of thedrive shaft 22 of the engine. Rotation of the gears 99 and 101 by theshaft 112 in response to the rotation of the crankshaft 22 will resultin a reduced fluid pressure in the inlet port 97 which will draw oilfrom the oil sump 91 through the inlet passage and conduit means 92 and93, 94 and 96 and into the inlet side of the pump 98. Operation of thepump will carry the oil through the gears 99 and 101 to the outlet port122 on the high pressure side of the pump 98. The oil under pressurefrom the outlet port 122 flows to the various bearings and to thesurfaces of the engine that require lubrication through a series ofconduit and passage means formed in the housing 68 and the crankcase 11and other parts of the engine. Such conduit and passage means includes apassage 123 which is formed in the housing 68 and the wall 17 of thecrankcase and which extends upwardly therein and to where the end of thepassage terminates in the surface to which the bracket 78 is secured.The passage 123 also communicates with a bypass passage 124 formed inthe housing 68 and the opposite end of which terminates in the inletpassage 96 that leads to the inlet port 97. The bypass passage 124 iscontrolled by a pressure relief valve 126 that is mounted in a passage125 intersecting the passage 124. The pressure relief valve 126 includesa piston 127 normally held against a pin 128 by a spring 129 that issecured in the passage 125 by a threaded plug 131. The plug 131 may besealed against the casing 68 by a gasket 134. The inlet side of the pumpis connected to the spring or low pressure side of the piston 127 by apassage 132 extending between the passages 124 and 125. The spring 129is so calibrated that when the pressure of the fluid in the passage 123reaches a predetermined value the piston 127 will be pushed against thespring 129 until the passage 124 is opened from the outlet passage 123to the inlet passage 96. This will maintain a substantially constantpredetermined pressure in the outlet passage 123. The valve 126 may beremoved or installed through the opening 125 in which the plug 131 issecured. The plug 131 is accessible from the exterior of the engine 10.

The bracket 78 is formed to provide an inlet cavity 136 with which theupper end of the passage 123 communicates. The bracket 78 is also formedto provide an outlet cavity 137 also opening into the surface on whichthe bracket 78 is secured. The cavities 136 and 137 are connected by apassage 138 in the bracket 78. An oil filter 139 which is secured to thebracket 78 by a bolt 141 is also included within and forms a part of thepassage 138, to the end that the oil flowing through the passage 138from the cavity 136 to the cavity 137 will be cleaned. A pressure reliefvalve 142 is mounted in a cavity 143 in the bracket 78 that opensoutwardly from the inlet cavity 136. The cavity 143 forms a part of aby-pass passage 144 between the cavities 136 and 137. The pressurerelief valve includes a perforated casing 146 which is pressed into theopen end of the cavity 143 and which includes an inlet 147 controlled bya valve 148 and pressed by a spring 149 against a seat controlling thepassage 147. When the resistance to flow through the filter 139 reachesa predetermined value, the valve 148 will open the bypass passage 144between the cavities 136 and 137. The valve 142 may be removed orinstalled in the bracket 78 when the bolts 79 securing the bracket tothe housing 68 are removed.

The outlet conduit and passage means for lubricating the various partsof the engine also includes a metering jet 151. The outlet cavity 137 isat all times in open communication with the metering jet 151 which ispressed into the reduced end of a passage formed in the housing 68between the surface supporting the bracket 78 and the cavity 71 betweenthe housing 68 and the end 17 of the crankcase 11. The reduced end ofthe metering jet 151 is directed toward the gear 119 which is employedin driving the pump 98. It will be apparent that rotation of the gear119 will form a mist of the oil which will tend to lubricate all of themoving parts in the cavity 71.

One rotating part in the cavity which will be lubricated by the mistformed by the gear 119 is a fuel pump drive mechanism 153. Thismechanism includes a cam 154 mounted on the crankshaft end 72 adjacentthe gear 119. The cam 154 drives a plunger 156 mounted in a sleeve 157pressed into an opening in the housing 68 which extends from the cavity71 in the housing 68 to the cavity 81 in the bracket 78. The bracket 78is formed to provide a socket aligned with the plunger 156 and in whichthe cylindrical end 158 of the casing 159 of a fuel pump 161 is securedby a screw 162. A cavity 163 beyond the end 158 of the casing 159receives a resilient coupling 164 connecting the end of the plunger 156with the reciprocating shaft 166 of the fuel pump 161. The mist in thecavity 71 will collect on the plunger 156 for lubricating the plunger156 and the coupling 164 connecting the plunger 156 with the shaft 166.The mist in the cavity 71 will also collect on the seal 77 forlubricating the running contact between the seal and the hub 73. Themist in the cavity 71 also will lubricate the shafts 189 and 112 for theoil pump 98, the gear 114 driven by the gear 119 and the shaft 118 whichdrives the distributor for the engine 19. The coupling 113 also will belubricated through a passage 118 by oil resulting from the mist andwhich may collect in a pocket 115.

The outlet cavity 137 also communicates with a passage 167 which isformed partly within the housing 68 and partly between the housing 68and the end wall 17 of the block 11. The passage 167 communicates withthe outlet end of a bypass passage 168 formed partly within the housing68 and partly within the end wall 17 of the block 11. The opposite endof the bypass passage 168 communicates with the passage 167. The passage168 also has intermediate ends terminating in a surface to which an oilcooler support 169 is secured on a gasket 175 to the outer surface ofone of the side walls 28 of the block 11 directly opposite the end wall17. When the engine is started the oil from the outlet cavity 137normally tends to flow into and through the passage 167 but this may beprevented by a thermostatically actuated temperature control valveindicated at 171. The valve 171 is located partly in the cavity 137 andpartly in a cavity 172 in the surface of the housing 68 to which thebracket 78 is secured. The control valve 171 has a thermostatic element173 which is held by a spring 174 against a perforated support or spider176 which is pressed into the upper enlarged part of the cavity 172.When the oil flowing through the cavity 137 becomes heated to apredetermined value the capsule or element 173 will expand to move avalve 177 secured on a shaft 178 that projects from the element 173through a centrally disposed opening in the spider 176. When the valve177 is moved far enough it will be apparent that it will close theorifice 179 which forms a part of the communication between the cavity137 and the passage 176. A spring 181 may be disposed in an enlargedpart of the passage 176 adjacent the orifice 179 and may be compressedbetween the housing 68 and the valve 179. The spring 181 will tend toopen the valve 177 whenever the temperature of the oil in the cavity 137cools the elements 173 sufficiently to permit opening of the valve. Whenthe valve 177 is closed on the orifice 179 it will be apparent that theoil from the cavity 137 will be compelled to flow through the bypasspassage 168 and through the passage 180 in the oil cooler whichcommunicates with the ends of the bypass passage 168 that terminate inthe surface supporting the oil cooler 170.

The lower end of the passage 167 is formed in the housing 68 to providebranch passages 182 which communicate with a pair of parallel oilgalleries 183, the ends of which open through the wall 17 of the block11. The oil galleries 183 extend through the bosses 51 supporting thevalve lifters 49 and the various webs between the bosses and thetransverse walls 16, 17, 18 and 19 of the crankcase 11. The passages 183intersect the valve lifters 49 but the valve lifters 49 havecircumferential recesses 184 which cause the passages 183 to continuearound the valve lifters 49. One of the passages 183 communicatesthrough passages 186 and 187 respectively with alternate bearings 23 ofthe camshaft 24 and with alternate bearings 21 of the crankshaft 22 andthe other passage 183 similarly communicates with the other alternatebearings of the camshaft 24 and the crankshaft 22. The passages 186simply terminate in the bearings 23 for the camshaft 24. However, thepassages 187 terminate in arcuate grooves 188 that extend around thebushings 189 cmbodied in the bearings 21 for the crankshaft 22. Thebushings are constructed to provide arcuate internal grooves 191 at theupper and lower parts thereof, as illustrated in FIGURE 14. The grooves191 at the upper parts of the bearings communicate with the grooves 188through the passages 192 while the grooves 191 in the lower parts of thebushings communicate with the grooves 188 through passages 193. Withthis construction it will be apparent that the parts of the bushings 189between the inner grooves 191 will support the largest loads imposed onthe crankshaft by the operation of the pistons of the engine and thatthese parts will be lubricated from the grooves 191 by rotation of thejournals 26 of the crankshaft 2.1. The bearings 194 for the connectingrods 36 will be lubricated by obliquely disposed passages 196 that areformed in the crankarms supporting the crankpins 34. The pasages 196slope with respect to the crankarms so that the ends of the pasageswhich terminate in the main bearing bushings 189 form acute angles withrespect to the grooves 191 on the sides of the bushings 189 toward whichthe crankarms rotate on the inward stroke for each of the pistons of theengine. This will 1 cause the obliquely disposed ends of the passages196 to tend to scoop the oil from one of the passages 196 when thepistons are moving in one direction.

The pistons 33 are lubricated by oil thrown out of the connecting rodand main bearings of the engine and which collects upon the inner wallsof the cylinders 29. The wristpins 197 for the pistons are lubricated byopenings 198 in the wristpin bearings 199 of the pistons 33. The mist inthe crankcase and resulting from the oil thrown I out of the main andconnecting rod bearings of the engine also tend to collect in pockets201 between the piers 262 supporting the wristpin bearings 199 and fromwhich the oil will flow into the passages 198.

The valve lifters 49 are lubricated by the oil in the circumferentialgrooves 134. The grooves 184 supply oil through radial passages 263 toinner circumferential passages 204 formed in the valve lifters 49. Thevalve lifters also have cavities or chambers 206 therein which are alsosupplied through radial passages 207 with oil from the passage 204.Receptacles 208 secured in the valve lifters 49 by the sockets 209 haveopenings 211 therein which are adapted to communicate with openings 212in the sockets 209 that in turn communicate with openings 213 in theends of the push rods 48 engaging the sockets 209. The push rods arehollow push rods thereby providing passages 214 therein that extend fromone end to the other of the push rods. Meter valves 216 are disposedbetween the receptacles 208 and the adjacent surface of the sockets 209.There is some space for movement of the valves 216 between thereceptacles 208 and the sockets 269 thereby causing the valves to engagefirst the receptacles and then the sockets. This periodically closes thepassages 212 in the sockets 209 that communicate with the openings 213and the passages 214 in the push rods 48. This tends to provide meteredquantities of oil from the cavities 206 which are subject to full engineoil pressure to the passages 214 in the push rods 48. The oil in thepassages 214 is adapted through openings 218 in the ends of the pushrods to lubricate sockets 217 in the rocker arms 44 which are engaged bythe ends of the push rods. The supports 46 for the rocker arms 44 alsoembody hemispherical bearings 219 that are secured to the supports 46 bynuts 221. The hemispherical bearings 219 and the surfaces of the rockerarms 44 engaged by the bearings 219 are adapted to be lubricated bypassages 222 and 223 which are formed in the rocker arms 44 and the pushrods 48, respectively. The passages 223 are sometimes directly oppositethe passages 222, in which event jets of oil from the passages 223 willbe directed on the bearings 219 through the passages 222. However, thepush rods 48 tend to rotate which causes the oil to be supplied onlyintermittently to the bearings 219. At other times the oil from theopening 223 will simply be directed in different directions throughoutthe compartments containing the rocker arms 44. This oil will be formedinto a mist by the operation of the valve actuating mechanism of theengine and will lubricate the stems of the valves 38 and 39, the valvesprings 43 and the ends of the rocker arms 44 engaging the valve stems.The oil in the rocker arm compartments will tend to collect on the wallsand flow by gravity into the lower parts of. the rocker arm compartmentswhere it then will flow into the conduits 56 which surround the pushrods 43 and which connect the rocker arm compartments to the crankcaseof the engine. It will be noted that the conduits =56 slope downwardlyfrom the rocker arm compartments so that the oil will return by gravityflow through the conduits 56 to the crankcase.

The ends of te passages 183 opposite the housing 68 may be closed in anysuitable manner as by employing threaded plugs indicated at 224. 7

It will be noted that the cavity 61 containing the gears 64 and 66communicates through a passage 226 in the end wall 16 with the oil sump91 in the lower part of the crankcase 11 and the oil pan 88, The oil pan88 continues beyond the end wall 16 and engages the lower part of thehousing '57 thereby partly closing the cavity 61 between the housing 57and the end wall 16. The passage 226 is formed at the lower extremity ofthe wall 16 and low enough so that oil will normallyflow from the oilsump 91 into the lower part of the cavity 61 Where it will be engaged bythe teeth of the gear 66. The teeth of the gear 66 will tend to pick upthe oil and carry it upwardly to the gear 64. The operation of the gearsalso will tend to cause a mist in the cavity 61 which will tend tolubricate a seal 62. It is proposed to provide an oil return for theexcess oil that may be carried upwardly by the teeth of the gear 66 andinto the cavity 61. For this purpose it is proposed to provide a cavity227 in the rear wall and the housing 57 about opposite the axis of thecamshaft 67 and on the side of the gear toward which the teeth of thegear rotate from the bottom of the gear upwardly. The cavity 227 isconnected to the interior of the crankcase 11 by a passage 228. When thegear rotates the teeth will carry excess oil upwardly where it will bethrown out into the cavity 227 and returned to the crankcase through thepassage 228.

What is claimed is: p

A lubricating systernfor an internal combustion engine having acrankcase with a crankshaft and a camshaft mounted therein and having ahousing at one end thereof with engine accessory devices associatedtherewith and comprising, a lubricating oil pump disposed in said housngand havingan inlet in said crankcase, pump inlet passage means formed insaid crankcase and said housing and leading from said inlet to saidpump, pump outlet passage means formed in said housing and saidcrankcase and leading from said pump to the bearings for said crankshaftand said camshaft, said outlet passage means within said housing beingformed to provide outlet passage means ends terminating in a surface ofsaid housing, a bracket forming a part of said housing and engaging saidsurface and having cavities therein and with one of said cavitiescommunicating with each of said ends, filter passage means formed insaid bracket and communicating with said cavities, an oil filter securedto said bracket and communicating with said cavities through said filterpassage means, a bypas passage formed in said bracket between saidcavities, a pressure relief valve mounted in said bracket andcontrolling said bypass passage, means removably securing and sealingsaid housing to said crankcase with said inlet passage means in saidcrankcase registering with said inlet passage means in said housing andwith said outlet passage means in said housing registering with saidoutlet passage means in said crankcase and with said inlet and outletpassage means in said crankcase and said housing sealed against leagageof oil between said inlet and said outlet passage means, and meansremovably securing and sealing said bracket to said housing surface withsaid ends registering with said cavities and with sad cavities and endssealed against leakage of oil between said cavity ends, and saidpressure relief valve being accessible through one of said cavities whensaid bracket is removed from said housing.

References Cited in the file of this patent UNITED STATES PATENTS

